UMLS:C0476089 - FACTA Search

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Query: UMLS:C0476089 (endometrial cancer)
11,379 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We have examined the effects of protein kinase-C (PKC) activation on expression of the six known insulin-like growth factor-binding proteins (IGFBPs) by human endometrial carcinoma cells. Each of six known IGFBPs was expressed in one or more of the three cell lines examined. The addition of 10(-7) M 4 beta-phorbol 12-myristate 13-acetate (PMA) to HEC-50 and HEC-1B cells resulted in changes in cell morphology, growth inhibition, activation of PKC, and an increase in expression of IGFBP-1. PMA had no effect on these parameters in the Ishikawa cell line, which did not express IGFBP-1. In HEC-50 cells, the effect of PMA was blocked by the concomitant addition of the PKC inhibitor staurosporin and the simultaneous addition of cycloheximide. PMA also resulted in an increase in IGFBP-3 in HEC-50 cells and an increase in IGFBP-6 expression in HEC-1B cells. In contrast, IGFBP-3 expression was down-regulated by PMA in HEC-1B and Ishikawa cells. The abundance of IGFBP-2 and IGFBP-5 mRNAs was also reduced in HEC-1B and Ishikawa cells, respectively. IGFBP-4 was expressed only in HEC-50 cells and was not affected by PMA treatment. These data establish a role for the PKC pathway in regulation of expression of IGFBP-1, -2, -3, and -5 in endometrial adenocarcinoma cells and illustrate the complexity of cell type-specific expression of the IGFBPs.
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PMID:Phorbol esters differentially regulate the expression of insulin-like growth factor-binding proteins in endometrial carcinoma cells. 128 Feb 5

The production of insulin-like growth factor binding proteins (IGFBP) with special reference to human IGFBP-1 was evaluated in five endometrial adenocarcinoma cell lines (HEC 1A, HEC 1B, KLE, RL952 and AN3CA) in continuous culture. Two of the cell lines (HEC 1B and KLE) produced immunoreactive IGFBP-1. The production was inhibited by clomiphene and progesterone, whereas estrogen, cortisol and insulin had no effect on IGFBP-1 secretion. The two cell lines which secreted immunoreactive IGFBP-1 also had IGF-I receptors, whereas the cell lines RL952 and AN3CA, not producing IGFBP-1, had no saturable IGF membrane binding sites. IGF-I receptor binding to HEC 1B and KLE cells was inhibited in the presence of purified IGFBP-1. In addition to IGFBP-1, the endometrial cancer cells secreted several other forms of IGFBPs as determined by cross-linking. Immunoprecipitation of IGF-BP complexes with a polyclonal antiserum against IGFBP-3 indicated that all cell lines secreted binding proteins antigenically related to IGFBP-3 with molecular weights ranging from 20 to 39 kDa.
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PMID:Human endometrial adenocarcinoma cell lines HEC 1B and KLE secrete insulin-like growth factor binding protein-1 and contain IGF-I receptors. 171 Sep 98

The insulin-like growth factor (IGF) system is thought to function as a mediator of steroid hormone actions in the endometrium. IGFs (IGF-I and IGF-II) are also potent mitogens in endometrial cancer. The biological actions of IGFs are modulated by specific binding proteins (IGFBP)--6 cloned and sequenced so far--which may either inhibit or enhance the effects of IGF at the cellular level. In the endometrium, IGFBP-1 gene expression is stimulated by progesterone and inhibited by insulin, while IGFBP-1 inhibits the mitogenic action of IGF-I. In this study, we used a quantitative reverse transcriptase polymerase chain reaction (RT-PCR) to investigate IGFBP-1, IGFBP-2, IGFBP-4, IGFBP-5 and IGFBP-6 gene expression in endometrial cancer tissues. Endometrial cancer tissue samples were collected from 20 women (aged 54-79 yrs) with stage I to II well-differentiated endometrial adenocarcinoma. Samples of normal endometrium (n = 14) obtained from women undergoing tubal ligation in various phases of the menstrual cycle, and normal early-pregnancy endometrium (decidua) were studied for comparison. In endometrial cancer tissues, the IGFBP-1 mRNA was undetectable or minimally expressed when studied by RT-PCR. The mean (+ SD) levels of IGFBP-2 and IGFBP-4 and IGFBP-5 mRNAs in endometrial cancer tissues did not differ from those in normal endometrium, in which no cyclic variation was observed, suggesting that the genes encoding IGFBP-2, IGFBP-4 and IGFBP-5 are not hormonally regulated in the endometrium. The IGFBP-6 mRNA expression showed a significant cyclic variation in normal endometrium, with low levels in late-proliferative and early- to mid-secretory phases and high expression in late-secretory and early-proliferative phases. In endometrial cancer tissues, the mean IGFBP-6 mRNA level was similar to that in cycling endometrium during the peri-ovulatory period. In summary, a continuous stimulation of the endometrial epithelial cells by IGFs with suppressed IGFBP-1 expression may lead to an imbalance in the IGF system of the endometrium and trigger an uncontrolled cell proliferation, ultimately resulting in malignant transformation.
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PMID:Suppressed expression of insulin-like growth factor binding protein-1 mRNA in the endometrium: a molecular mechanism associating endometrial cancer with its risk factors. 752 16

In uterine tissue, estrogen regulates various components of the insulin-like growth factor system; however, there are few suitable in vitro systems to examine these effects. Here we have examined the effects of 17-beta estradiol (E2) on expression and synthesis of insulin-like growth factors (IGF-I and IGF-II) and the insulin-like growth factor binding proteins (IGFBPs) by Ishikawa human endometrial cancer cells. Using a semiquantitative reverse transcription-polymerase chain reaction (RT-PCR) assay, we demonstrated that both E2 and 4-hydroxy-tamoxifen (OHT) enhanced IGF-I expression but had no effect on IGF-II expression. The pure antiestrogen ICI 182,780 had no effect on IGF-I expression and partially blocked the E2 and OHT effect on IGF-I expression. The effect of epidermal growth factor (EGF), which is able to mimic some of the effects of E2 in Ishikawa cells and uterine tissue, was also examined. EGF, unlike E2, did not increase IGF-I expression but rather resulted in a significant decrease in IGF-I messenger RNA (mRNA) levels. EGF also resulted in a small, nonsignificant increase in IGF-II mRNA levels. IGFBP-3, -5, and -6 mRNAs were detected by Northern blot analyses of Ishikawa cells RNA. However, only IGFBP-3 was consistently detected by ligand blotting of conditioned medium. E2 had no significant effect on expression of any of the binding proteins, whereas EGF increased IGFBP-5 mRNA levels. These data provide the first in vitro demonstration of regulation of IGF-I expression by E2. The Ishikawa cell line may provide a useful model to further investigate the molecular mechanisms underlying E2 regulation of IGF-I expression. Furthermore, we have demonstrated a clear dissociation of the effects of E2 and EGF on IGF-I expression in this cell line.
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PMID:Expression of insulin-like growth factors and their binding proteins in the estrogen responsive Ishikawa human endometrial cancer cell line. 752 33

Insulin is a major regulator of circulating insulin-like growth factor (IGF)-binding protein-1 (IGFBP-1), suppressing the hepatic production of IGFBP-1. Postmenopausal age, obesity, hypertension, and impaired glucose tolerance, which are known risk factors for endometrial cancer, are all associated with hyperinsulinemia and insulin resistance. In this study, we investigated the relationship among serum insulin, glucose, insulin-like growth factors (IGF-I and IGF-II), and IGFBP-, -2, and -3 in 32 nondiabetic postmenopausal women with endometrial cancer and in 18 healthy controls. The mean fasting levels of glucose and insulin were higher, whereas the mean basal IGF-I, IGF-II, and IGFBP-3 levels were lower in the endometrial cancer patients than in the healthy control subjects. The mean fasting IGFBP-1 and IGFBP-2 levels did not differ between the groups, and no correlation was found between fasting insulin and IGFBP-1 concentrations or between insulin and IGFBP-2 concentrations in either of the study groups. During an oral glucose tolerance test, the mean glucose levels at 1 and 3 h as well as the mean insulin level at 3 h were significantly higher in the endometrial cancer patients than in the controls, and the area under the glucose curve was larger in the first group. An oral glucose load resulted in a similar fall in serum IGFBP-1 levels in endometrial cancer patients and controls (51% and 55% at 3 h). When the cancer patients were divided into two subgroups according to the body mass index (kilograms per m2), the obese group had higher glucose and insulin indices than the nonobese group. No difference was found by the same measures in healthy controls. The fasting serum IGFBP-1 levels tended to be lower in the obese than in the normal weight subjects, but the difference did not reach statistical significance. In summary, these results provide preliminary evidence that the inverse relation between fasting insulin and IGFBP-1, well established in children and young adults, disappears in elderly women, although short term suppression by insulin still occurs. Further, our data indicate that in addition to carbohydrate metabolism, postmenopausal women with endometrial cancer have alterations in their circulating IGF system compared to controls.
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PMID:Relationship between carbohydrate metabolism and serum insulin-like growth factor system in postmenopausal women: comparison of endometrial cancer patients with healthy controls. 768 14

Transforming growth factor-beta 1 (TGF-beta 1) enhanced cell proliferation in a concentration-dependent manner in a human endometrial cancer cell line, IK-90. Scatchard analysis of TGF-beta 1 receptor in IK-90 cells, using 125I-TGF-beta 1 as a ligand, revealed the presence of a class of high-affinity TGF-beta 1 receptors (2,000 sites per cell, KD = 74pM). Moreover, IK-90 cells produced and secreted TGF-beta 1: TGF-beta 1 messenger RNA was detected at 2.5 and 4.0 kb by Northern-blot analysis using 32P-labeled TGF-beta 1 cDNA as a probe, and TGF-beta 1 activity in conditioned medium by the inhibition of 3H-thymidine uptake into CCl 64 mink lung epithelial cells. We investigated the regulation of TGF-beta 1 receptor by 4 kinds of growth factor: epidermal growth factor (EGF) but not TGF-beta 1, insulin or insulin-like growth factor-1 increased the level of TGF-beta 1 binding sites in a concentration- and time-dependent manner. These findings suggest that TGF-beta 1 may be a potential autocrine growth factor in a human endometrial cancer cell line IK-90 and that this autocrine mechanism may be affected by EGF.
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PMID:Autocrine growth mechanism by transforming growth factor (TGF)-beta 1 and TGF-beta 1-receptor regulation by epidermal growth factor in a human endometrial cancer cell line IK-90. 839 35

A significant increase in endometrial cancer incidence in tamoxifen-treated breast cancer patients has been reported in many recent studies. The major growth stimulators of endometrial tumors are estrogens, but paradoxically, tamoxifen, a known antiestrogen, also stimulates their growth. The mode of action of estrogen can be partially explained by the modulation of insulin-like growth factor (IGF) autocrine or paracrine action. The purpose of the present study was to examine the involvement of the IGF system in the tamoxifen-stimulated growth of Ishikawa endometrial cancer cells by quantitating the IGF-I receptors and their phosphorylation, as well as membrane associated and secreted IGF-binding proteins (IGFBPs). Tamoxifen did not affect the number or affinity of IGF-I receptors. On the other hand, tamoxifen, similar to estradiol, increased IGF-I-stimulated tyrosine phosphorylation of cellular substrates. In contrast, in MCF-7 mammary cancer cells, tamoxifen reduced IGF-induced tyrosine phosphorylation in the presence of estradiol. The pure antiestrogen LY156758 did not affect Ishikawa basal cell growth but inhibited estradiol- and tamoxifen-induced growth. Growth inhibition by LY156758 of tamoxifen and estradiol-stimulated cells was accompanied by a corresponding inhibition of IGF-stimulated tyrosine phosphorylation. Tamoxifen caused a 3-fold decrease in membrane-associated IGFBPs. Moreover, a reduction in soluble IGFBPs was also observed, making the IGF peptides more available to the receptors. A parallel decrease in IGFBP-3 mRNA was also detected. These experiments suggest that tamoxifen, like estradiol, directly sensitizes endometrial cancer cells to the effects of IGFs that act through the type I receptor. Furthermore, the decrease in IGFBPs and the increase in tyrosine phosphorylation in the presence of tamoxifen provides a molecular mechanism that accounts for the uterotropic effects that are seen with tamoxifen therapy.
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PMID:Stimulation of endometrial cancer cell growth by tamoxifen is associated with increased insulin-like growth factor (IGF)-I induced tyrosine phosphorylation and reduction in IGF binding proteins. 860 78

Transcription-modulating drugs achieve their therapeutic effects through the modulation of gene transcription. To understand how selectivity is achieved, four groups of such drugs - including immunosuppressants, estrogen analogs, the antidiabetic thiazolidinediones, and the anti-inflammatory salicylates - will be discussed. The immunosuppressants cyclosporin A and FK506, when complexed with immunophilins, inactivate the protein phosphatase calcineurin, resulting in the inhibition of interleukin-2 gene activation. Another immunosuppressant, rapamycin, binds to the same immunophilin as FK506 but inactivates a protein kinase p70(s6k). Estrogen analogs tamoxifen and rolaxifene antagonize one estrogen receptor transactivation function (AF-2) and agonize another (AF-1). They modulate expression of a wide variety of genes, including transforming growth factor-alpha, insulin-like growth factor-1, and transforming growth factor-beta3, which are important for breast and endometrial cancer proliferation and bone maintenance respectively. The antidiabetic drugs thiazolidinediones bind and activate peroxisome proliferator-activated receptor gamma and suppress insulin resistance mediated by tumor necrosis factor-alpha. Salicylates inhibit transcription factor NFkappaB, which is important for immune and inflammatory responses. Continuing understanding of molecular mechanisms of such drugs not only helps to identify better drugs for these targets but should also provide an insight into developing future transcription-modulating drugs with better selectivity and reduced toxicity.
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PMID:Transcription-modulating drugs: mechanism and selectivity. 893 43

The function of cell surface-associated insulin-like growth factor-binding proteins (IGFBPs) is controversial. Both inhibition and facilitation of IGF action as well as IGF-independent effects have been reported. We examined the influence of endogenous cell surface-associated IGFBPs on IGF-I receptor (IGF-IR) function in Ishikawa endometrial cancer cells by comparing the effects of IGF-I and its truncated analog des-(1-3)-IGF-I on several components of the IGF-IR signal transduction pathway in the absence of significant amounts of soluble IGFBPs. IGF-I and des-(1-3)-IGF-I are known to have similar affinities for IGF-IR, although the affinity of des-(1-3)-IGF-I for IGFBPs is greatly reduced. Here we show that the two ligands were equipotent not only in IGF-IR binding but also in receptor activation in NIH 3T3 cells overexpressing IGF-IR and possessing a relatively small number of cell surface-associated IGFBPs. In contrast, des-(1-3)-IGF-I manifested a remarkably higher potency as compared with IGF-I in inducing short and middle term cellular responses in IGF-IR-transfected Ishikawa endometrial cancer cells possessing a high number of both the receptor and the cell membrane-bound IGFBP-3. Thus, this difference in the effects of IGF-I and des-(1-3)-IGF-I can be attributed to the attenuation of IGF-I-mediated IGF-IR signaling by membrane-bound IGFBP-3.
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PMID:Membrane-associated insulin-like growth factor-binding protein-3 inhibits insulin-like growth factor-I-induced insulin-like growth factor-I receptor signaling in ishikawa endometrial cancer cells. 919 61

In human endometrium insulin-like growth factor binding protein (IGFBP)-1 inhibits the mitogenic action of insulin-like growth factor (IGF)-I by inhibiting the binding of IGF-I to its receptor. Our purpose was to compare circulating levels of IGF-I and IGFBP-1 in women with and without endometrial cancer. We assessed circulating levels of IGF-I and IGFBP-1 and IGFBP-3 in 23 patients with endometrial cancer, 11 patients with uterine cervical cancer and 27 healthy control women. The mean circulating level of IGF-I decreased significantly following menopause but was not correlated with age in the control group. The body mass index was significantly higher in the endometrial cancer group than in the control group. Analysis of covariance showed that even after the data were adjusted to eliminate the influence of the body mass index, the circulating IGF-I concentration was higher in postmenopausal endometrial cancer patients than in postmenopausal control subjects. The mean circulating level of IGFBP-1 was significantly lower in postmenopausal cancer patients than in postmenopausal control subjects. There were no significant differences in the serum levels of IGF-I and IGFBP-1 in the patients with cervical cancer and the control group. In conclusion, an increased circulating concentration of IGF-I and a decreased circulating concentration of IGFBP-1 are associated with endometrial cancer especially in postmenopausal women.
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PMID:Increased circulating levels of insulin-like growth factor-I and decreased circulating levels of insulin-like growth factor binding protein-1 in postmenopausal women with endometrial cancer. 927 18

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